{"title":"High-yield production of lactide isomers from depolymerization of polylactic acid in supercritical carbon dioxide","authors":"Seda Sivri, Naime Aslı Sezgi, Cerag Dilek","doi":"10.1016/j.supflu.2024.106473","DOIUrl":"10.1016/j.supflu.2024.106473","url":null,"abstract":"<div><div>Chemical depolymerization of polylactic acid (PLA) was demonstrated in supercritical carbon dioxide medium. No catalyst, organic solvent or water was employed in the reaction. The primary feedstocks used in ring opening polymerization of PLA, lactide isomers, were produced with high yield. More specifically, lactides were produced as the sole nongaseous products with a 93 % yield based on the initial polymer mass at 200 °C and 310 bar in 120 min. The influences of the reaction temperature, time, and pressure on PLA depolymerization products were investigated. While the lactide yield and distribution were highly influenced by the reaction temperature and time, further improvement was attained with an increase in the pressure. The results demonstrate that supercritical CO<sub>2</sub> can be applied as a promising reaction medium for PLA degradation, providing a high-yield production of its feedstock. The process can enable green depolymerization of polylactic acid and promote its circular economy with a closed loop production.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106473"},"PeriodicalIF":3.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yutao Feng , Junyang Zhu , Hailong Cui , Ziyi Lu , Jinglong Li , Ying Wang , Chengqi Jiao , Xiaoqing Xiong
{"title":"Clean production and dyeing of fluorescent yellow dyes based on naphthalic anhydride in supercritical carbon dioxide","authors":"Yutao Feng , Junyang Zhu , Hailong Cui , Ziyi Lu , Jinglong Li , Ying Wang , Chengqi Jiao , Xiaoqing Xiong","doi":"10.1016/j.supflu.2024.106470","DOIUrl":"10.1016/j.supflu.2024.106470","url":null,"abstract":"<div><div>Supercritical carbon dioxide (scCO<sub>2</sub>) was selected as the medium for the synthesis and dyeing of four naphthalimide dyes (Y-1, Y-2, Y-3, and Y-4). They were synthesized through the reaction of 4-bromo-1,8-naphthalene dianhydride with various amines. These dyes demonstrated good photophysical properties and thermal stability, aligning with the prerequisites for scCO<sub>2</sub> dyeing. Consequently, the scCO<sub>2</sub> dyeing of polyester fabrics using these four dyes was investigated, and the optimal dyeing conditions were established in the range of 18<img>20 MPa, 120<img>130℃, and 80<img>90 min. Surface analysis confirmed the uniform distribution of the dyes on the fabrics, with no significant damage to the fabric structure under the dyeing conditions. Additionally, the dyed fabrics exhibited good color fastness to soap washing and friction with level 4 or above. Overall, the clean preparation and dyeing of naphthalimide dyes hold promise for reducing environmental pollution.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106470"},"PeriodicalIF":3.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Janet de los Angeles Chinellato Díaz , Marcelo R. Romero , María L. Goñi , Nicolás A. Gañán , Facundo Mattea
{"title":"Exploring the potential of supercritical carbon dioxide for eugenol impregnation in 3D printed polylactic acid structures","authors":"Janet de los Angeles Chinellato Díaz , Marcelo R. Romero , María L. Goñi , Nicolás A. Gañán , Facundo Mattea","doi":"10.1016/j.supflu.2024.106469","DOIUrl":"10.1016/j.supflu.2024.106469","url":null,"abstract":"<div><div>Biocompatible implants are essential for improving human health and longevity. Incorporating bioactive compounds, such as eugenol, into implant materials can improve biocompatibility and therapeutic efficacy. This study examines the effects of supercritical eugenol impregnation on the physical properties of 3D-printed polylactic acid samples produced by Fused Deposition Modeling. Impregnation was performed using a lab-scale high-pressure system, evaluating the impact of impregnation time on eugenol loading, distribution, and morphology. Fourier Transform Infrared spectroscopy confirmed homogeneous eugenol distribution with impregnation times exceeding 1 h, achieving loadings up to 12 wt%. Eugenol was released slowly over extended periods in a phosphate-buffered solution. Impregnated samples displayed more amorphous thermal behavior, with decreased Tg due to the plasticizing effect of the CO₂-eugenol mixture. Mechanical properties were slightly altered, with reduced stiffness and increased toughness. Microscopic deformations induced by impregnation could potentially enhance cellular adhesion, improving biocompatible material performance.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106469"},"PeriodicalIF":3.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Recovery of bioactive compounds from pineapple waste through high-pressure technologies","authors":"Felipe de Andrade Maia, Luiz Henrique Fasolin","doi":"10.1016/j.supflu.2024.106455","DOIUrl":"10.1016/j.supflu.2024.106455","url":null,"abstract":"<div><div>This study aimed to obtain bioactive compounds from the residue from pineapple (<em>Ananas comosus</em> L. Merril) juice processing, using supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE). The SFE were performed using ethanol as a co-solvent and evaluating different pressure, temperature, and co-solvent percentage. For the PLE, temperature and ethanol percentage were assessed. The best extraction conditions for SFE were 20 MPa, 60 °C, and 15 % ethanol, while for PLE they were obtained at 10 MPa, 100 °C with 50 % and 75 % ethanol. Both methods presented a higher concentration of bioactives than other recognized vegetable waste sources. However, it was observed that PLE showed a higher overall extract yield, phenolic compounds, flavonoids, carotenoids, and antioxidant activity. The main phenolic compounds identified were caffeic acid and ferulic acid. Therefore, pineapple residue is a potential source of bioactive compounds, and the pressurized liquid extraction technique proved more efficient for their recovery.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106455"},"PeriodicalIF":3.4,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extraction and isomerization of ultraviolet-absorbing substances, saclipins, from an edible cyanobacterium Aphanothece sacrum using subcritical water","authors":"Mitsuya Ito , Masaki Honda , Hakuto Kageyama","doi":"10.1016/j.supflu.2024.106459","DOIUrl":"10.1016/j.supflu.2024.106459","url":null,"abstract":"<div><div>The effects of the extraction conditions on the recovery and isomerization of the UV-absorbing saclipins from the edible cyanobacterium <em>Aphanothece sacrum</em> by subcritical water were investigated. The extraction temperature (100–160 ℃) did not affect the extraction efficiency of saclipins, but the pressure (5–15 MPa) had a significant effect. The saclipin B (<em>cis</em>-configuration) ratio in the extract increased with extraction temperature. Since saclipin A (<em>trans</em>-configuration) is predominant in the raw material, it is proposed that thermal-induced <em>cis</em>-isomerization occurs during the extraction process under elevated temperature conditions. Furthermore, we found that extraction with subcritical water resulted in higher extraction and isomerization efficiencies of saclipins than extraction with organic solvents. Extracts obtained by subcritical water extraction (SWE) exhibited antioxidant and anti-elastase activities and the degree of the activities was affected by the extraction temperature (i.e., saclipin isomer ratio). These findings could facilitate the development of sunscreens with enhanced skincare benefits, utilizing naturally-derived bioactive compounds.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106459"},"PeriodicalIF":3.4,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bruna Sgarioni, Luane C. Angeli, Matheus R. Andrade, Rubem M.F. Vargas, Eduardo Cassel
{"title":"Supercritical fluid extraction of yerba mate: Decaffeination, purification, encapsulation, and controlled release","authors":"Bruna Sgarioni, Luane C. Angeli, Matheus R. Andrade, Rubem M.F. Vargas, Eduardo Cassel","doi":"10.1016/j.supflu.2024.106456","DOIUrl":"10.1016/j.supflu.2024.106456","url":null,"abstract":"<div><div><em>Ilex paraguariensis</em> is a source of bioactive compounds, which have been demonstrated to mitigate neurological disorders and enhance athletic performance. This study aimed to decaffeinate yerba mate using supercritical fluid extraction, followed by caffeine purification. The purified extract was encapsulated in gelatin via spray drying, and its release profile was evaluated in simulated gastric fluid. A mathematical model was established to describe the release behavior of the encapsulated extract. The characterization of yerba mate leaves and extracts was conducted prior to and following purification via HPLC. The capsules were subjected to analysis using SEM, FTIR e TGA, while the release fluid was examined using ultraviolet spectroscopy. The optimized SFE process produced decaffeinated yerba mate and the resulting extract exhibited a caffeine purity of approximately 87 %. The capsules were observed to possess a spherical morphology and micrometric particle size, and the release profile was found to follow a first-order kinetic model.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106456"},"PeriodicalIF":3.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vesna Leontijevic , Tijana Fechter , Danilo Cantero , Philip Jaeger , Maria José Cocero
{"title":"Surface wettability of lignin materials from supercritical water hydrolysis of wood","authors":"Vesna Leontijevic , Tijana Fechter , Danilo Cantero , Philip Jaeger , Maria José Cocero","doi":"10.1016/j.supflu.2024.106458","DOIUrl":"10.1016/j.supflu.2024.106458","url":null,"abstract":"<div><div>To meet the demands of the evolving circular economy, there is a growing need for renewable resources as base materials for innovative, easily recyclable products. Lignin, the second most abundant biopolymer, has emerged as a promising source of aromatics and reinforcing agent in polymer composites. For the successful manufacturing of homogeneous composite materials, good bonding between the coexisting phases is essential to prevent the formation of voids and agglomerates. Therefore, understanding the surface properties of these materials is crucial for designing optimal composite compounds. In this study, the wettability of lignin-cellulose composites and lignin samples obtained through supercritical water hydrolysis (SCWH) of birch wood is investigated. The contact angle (CA) technique, specifically the sessile drop method, was employed to assess and compare the wettability of SCWH lignin with commercially available lignin and raw birch wood. The results provide insights into their surface energy, adhesion, and hydrophilic or hydrophobic characteristics under processing conditions. All samples exhibited hydrophilicity, with an initial CA approximately 40 °, except for raw birch wood, which had a higher initial CA of ∼ 64°. Notably, when lignin is accompanied by significant amounts of cellulose, different trends in CA changes over time were observed. The influence of pressure on the CA between water and these polymers was also analyzed, but no significant impact was detected. This research advances the development of lignin-based materials with tailored surface properties for various industrial applications.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106458"},"PeriodicalIF":3.4,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yaneth Machaca Monroy , Patrícia Berilli , Sara Fraga , Adilson Sartoratto , Marili Villa Nova Rodrigues , Gerardo Fernández Barbero , Antonio José de Almeida Meirelles , Guilherme José Máximo , Mário Roberto Maróstica Júnior , Klicia Araujo Sampaio
{"title":"Araçaúna (Psidium myrtoides) flour: Sequential extraction with supercritical carbon dioxide and pressurized fluids","authors":"Yaneth Machaca Monroy , Patrícia Berilli , Sara Fraga , Adilson Sartoratto , Marili Villa Nova Rodrigues , Gerardo Fernández Barbero , Antonio José de Almeida Meirelles , Guilherme José Máximo , Mário Roberto Maróstica Júnior , Klicia Araujo Sampaio","doi":"10.1016/j.supflu.2024.106457","DOIUrl":"10.1016/j.supflu.2024.106457","url":null,"abstract":"<div><div>Araçaúna (<em>Psidium myrtoides</em>) is a native fruit from the Brazilian Atlantic Forest. It was studied for the proximate composition of its flour and sequential extraction using supercritical fluid extraction (SFE) in the first stage with CO<sub>2</sub> and pressurized liquid extraction (PLE) with ethanol and water in the second and third stages, respectively, at 50°C and 60°C. The proximate analysis revealed essential information about the flour regarding the content of protein, carbohydrates, lipid, ash and moisture. The sequential extraction at 60°C resulted in high yields (42.22 %). The first stage using SFE captured the volatile fraction, notably 1,4-diethylbenzene, which corresponds to 53.70 % of the total volatile compounds identified in the araçaúna. Comparing the second and third stages, the third stage with water at 50°C produced the highest levels of phenolic compounds (33.06±2.26 mg GAE/g extract), total monomeric anthocyanins (3.91±2.10 mg C3G/g extract), antioxidant activity by ORAC (415.13±13.66 µmol TE/g extract) and FRAP (747.16±18.49 µmol TE/g extract), and cyanidin-3-glucoside as the predominant compound (4.83 % w/w).</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106457"},"PeriodicalIF":3.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adenilson Renato Rudke , Cristiano José de Andrade , Sandra Regina Salvador Ferreira
{"title":"High-purity κ-carrageenan from Kappaphycus alvarezii algae for aerogel production by supercritical CO2 drying","authors":"Adenilson Renato Rudke , Cristiano José de Andrade , Sandra Regina Salvador Ferreira","doi":"10.1016/j.supflu.2024.106454","DOIUrl":"10.1016/j.supflu.2024.106454","url":null,"abstract":"<div><div>Carrageenan, a polysaccharide mostly extracted from <em>Kappaphycus alvarezii</em> (KA), is valuable for cosmetic and food uses due to large quantities of κ-carrageenan. High-pressure sequential extractions can recover high-purity carrageenan from KA, adequate for aerogel production. The biopolymer properties such as size, shape, and sulphate groups affect the gel form and aerogel characteristics. In this work, aerogels were obtained by supercritical CO<sub>2</sub> drying, and cryogels by freeze-drying, using high-purity carrageenan, recovered by sequential high-pressure extractions (HP), and commercial carrageenan (CC). The results indicated that HP samples showed higher volumetric shrinkage (96 %), firmness (254 N), and envelope density (0.008 g.cm<sup>−3</sup>) compared to CC samples. Aerogels presented characteristics of pore volume, surface area, and density suggesting supercritical drying as feasible method to produce porous materials. Besides, the aerogels present valuable properties compared to cryogel, including high firmness, useful for applications in packages, scaffolds, or delivery systems, a tendency that must be increasingly explored.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"217 ","pages":"Article 106454"},"PeriodicalIF":3.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhuobin Zhao , Jianxin Liao , Qinghua Deng , Jun Li , Zhenping Feng
{"title":"Flow mechanism and back gap windage loss of a sCO2 radial inflow turbine with impeller scallops","authors":"Zhuobin Zhao , Jianxin Liao , Qinghua Deng , Jun Li , Zhenping Feng","doi":"10.1016/j.supflu.2024.106453","DOIUrl":"10.1016/j.supflu.2024.106453","url":null,"abstract":"<div><div>The Internal flow mechanisms and windage loss in impeller back gap of a supercritical carbon dioxide (sCO<sub>2</sub>) radial inflow turbine with scallops are comprehensively investigated in this paper. The study emphasizes the effects of scallop depth and leakage outlet pressure. The results indicate that scallop structures lead to a degradation in overall turbine performance. Under design conditions, a turbine with a scallop depth ratio of 0.5 exhibits a 3.7 % reduction in efficiency and a 3.4 % decrease in total power compared to no scallop configuration. Furthermore, as scallop depth increases, the skin friction coefficient decreases in the disk gap while it increases for the seal in the impeller back gap. Increasing leakage outlet pressure reduces the leakage flow rate and skin friction coefficient. Fitted models for skin friction coefficient are proposed respectively. The conclusions providing valuable insights for designing and optimizing sCO<sub>2</sub> radial inflow turbines with scallops.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"216 ","pages":"Article 106453"},"PeriodicalIF":3.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}